This invention relates generally to a disposable diaper and, more particularly, to an improved disposable diaper having a construction with increased absorbent material in the area of maximum wetting.
All practical disposable diaper designs have been based on the use of a flat absorbent pad of relatively uniform thickness. The use of a rectangular pad poses two problems; one of fit and one of placement of absorbent material where it is most needed. These problems are in a way related and pose a dilemma. With a standard rectangular pad, the fit problem is caused by an excess of material in the crotch area, yet this is the very location where extra material is needed for moisture absorption. In effect, this excess is displaced to the edges where it creates extra bulk when it is really needed in the center section for absorbency.
The above problem has had extensive consideration, as is shown by the voluminous patent literature. Examples of patents showing either a built-up or contoured crotch area, or both, are those to Woody, U.S. Pat. Nos. 1,490,303; Budwig et al., 1,694,161; Fridolph, 2,122,417; Morin, 2,788,003; Tomlinson, 2,866,460; Tschappat, 3,176,688; Foote, 3,461,871; and others.
Disposable diapers are made in huge quantities and sold at a very low unit cost. As such, they are a highly competitive product. There is extreme pressure to develop the simplest possible designs and manufacturing techniques compatible with supplying a high quality product to the marketplace.
One such improved design is shown in applicant's earlier patent, U.S. Pat. No. 3,794,033. In this design, two symmetrically opposite cuts were made in the sides of the diaper. These began at or near a front corner and angled inwardly, about 1/4 to 1/3 of the distance toward the opposite rear corner. This resulted in the formation of two triangular flaps that were folded inwardly so as to overlap in the crotch area and give a generally hourglass-shaped configuration. A dual purpose was accomplished; a form fitting construction was created at the crotch area and a double or triple thickness of absorbent material was provided at the area where it was most needed.
Unfortunately, the designs shown in U.S. Pat. No. 3,794,033 are hard to manufacture on high speed equipment because the angling cuts from the edge are difficult to place accurately and the slitting equipment to make them presents a severe maintenance problem. The basic design also suffers somewhat since most versions do not place as much additional padding in the most critical wetting area as is desired.
Accordingly, one object of the present invention is to offer a disposable diaper with additional absorbent material positioned at the most critical wetting area.
Another object is to present a contoured diaper that is readily applied and is more comfortable to wear.
A further object is to provide a diaper with a built-up crotch portion that lends itself to simple and economical manufacturing techniques.
These and other objects of the invention will become apparent upon reading the following specifications in conjunction with the attached drawings.